Hidden sector explanation of $B$-decay and cosmic ray anomalies

There are presently several discrepancies in b→sℓ+ℓ- decays of B mesons suggesting new physics coupling to b quarks and leptons. We show that a Z′, with couplings to quarks and muons that can explain the B-decay anomalies, can also couple to dark matter in a way that is consistent with its relic abundance, direct detection limits, and hints of indirect detection. The latter include possible excess events in antiproton spectra recently observed by the AMS-02 experiment. We present two models, having a heavy (light) Z′ with mZ′∼600(12) GeV and fermionic dark matter with mass mχ∼50(2000) GeV, producing excess antiprotons with energies of ∼10(300) GeV. The first model is also compatible with fits for the Galactic center GeV gamma-ray excess.